It said that just 23% of the planet's landmass can now be
considered "wilderness" - places that do not have industrial
level activity within them. Wilderness areas do not
grow back once they are gone.

Here is where the world's remaining wilderness can be
found:

Australia: Desert

caption

The Tanami Desert in Australia's Northern Territory.

source

REUTERS/David Gray

The researchers identified Australia's deserts as one of the
planet's last remaining wilderness areas.

Australia's deserts are the only home for some animals, but the
areas are under threat from climate change and mining and
agriculture.

"Already we have lost so much. We must grasp this opportunity to
secure the wilderness before it disappears forever," the
researchers write.

The US: Alaska's arctic tundra

caption

A caribou skull sits on the tundra near the village of Anaktuvuk Pass in Alaska.

source

AP Photo/Al Grillo

"Wild places are facing the same extinction crisis as
species. Similarly to species extinction, the erosion of the
wilderness is essentially irreversible," the researchers
state.

Much of the wild places in the US are in Alaska, which has
large areas of tundra.

The most severe threat to Alaska's tundra is climate
change, but other threats include the construction of pipelines
and the search for oil and gas, which can kill wildlife,
according to National Geographic.

Canada: Boreal forest

caption

Canada's boreal forest runs north towards Whitehorse, Yukon.

source

REUTERS/Andy Clark/Files

Canada's boreal forests are one of the world's largest remaining
wilderness areas, the researchers found.

"The boreal forest is the most intact ecosystem on the
planet and holds one-third of the world's terrestrial carbon,"
according to the study.

As Brazil's president, Bolsonaro will control nearly
two-thirds of the Amazon, which cools the planet and is home to
many indigenous people. He has argued that too many
environmentally protected areas are hampering the country's
development.

Russia

caption

A car drives along a forest road in the Krasnoyarsk region, Russia.

source

REUTERS/Ilya Naymushin

Russia has more wilderness areas than any other country on earth,
the researchers found.

They did not include Antartica, because activities like mining
are banned there.

They calculated that 100 years ago, only 15% of the
planet's surface was used to grow crops and raise
livestock. Today, more than 77% of the land
(excluding Antarctica) and 87% of the ocean has been modified by
the direct effects of human activity.